Cooling device for fuel cell system and control method thereof
AssigneeNissan Motor Co., Ltd.
InventorTetsuo Uozumi
Life of this patent
Estimating the term…
Abstract
The efficiency of the fuel cell system is increased. This is enabled by controlling a bypass amount of cooling liquid for a conductivity reduction device such as an ion removal device in response to the operating state of the fuel cell system before the conductivity exceeds the permitted limiting value. The device is provided with a recirculation passage 10 which recirculates cooling liquid between a fuel cell 2 and a heat exchanger 5, a bypass passage 11 having an ion removal filter 4 therein, and a control device 1 which controls solenoids 6, 7 to increase a bypass ratio when the conductivity exceeds the permitted value.
Claims14
A cooling device using a cooling medium for a fuel cell stack, comprising:
- a heat exchanger which cools the cooling medium;
- a cooling passage through which the cooling medium is circulated between the fuel cell stack and the heat exchanger;
- a pump which pressurize the cooling medium in the cooling passage for circulation;
- a bypass passage which bypasses the fuel cell stack to directly circulate a part of the cooling medium discharged from the pump to the heat exchanger;
- an electrical conductivity reducing mechanism which reduces an electrical conductivity of the cooling medium passing through the bypass passage;
- a valve which regulates a bypass amount of the cooling medium passing through the bypass passage;
- a sensor which detects an electrical conductivity of the cooling medium;
- and
- a programmable controller programmed to:
- determine if the electrical conductivity is larger than a predetermined conductivity;
- control the valve to increase the bypass amount when the electrical conductivity is larger than the predetermined conductivity;
- determine if a predetermined condition related to an operation of the fuel cell stack holds;
- and
- control the valve to prevent the bypass amount from becoming zero when the electrical conductivity is not larger than the predetermined conductivity and the predetermined operation condition holds.
A cooling device using a cooling medium for a fuel cell stack, comprising:
- a heat exchanger which cools the cooling medium;
- a cooling passage through which the cooling medium is circulated between the fuel cell stack and the heat exchanger;
- a pump which pressurize the cooling medium in the cooling passage for circulation;
- a bypass passage which bypasses the fuel cell stack to directly circulate a part of the cooling medium discharged from the pump to the heat exchanger;
- an electrical conductivity reducing mechanism which reduces an electrical conductivity of the cooling medium passing through the bypass passage;
- a valve which regulates a bypass amount of the cooling medium passing through the bypass passage;
- a sensor which detects an electrical conductivity of the cooling medium;
- means for detecting an electrical conductivity of the cooling medium;
- means for determining, if the electrical conductivity is larger than a predetermined conductivity;
- means for controlling the valve to increase the bypass amount when the electrical conductivity is larger than the predetermined conductivity;
- means for determining if a predetermined condition related to an operation of the fuel cell stack holds;
- and
- means for controlling the valve to prevent the bypass amount from becoming zero when the electrical conductivity is not larger than the predetermined conductivity and the predetermined operation condition holds.
A control method for a cooling device which cools a fuel cell stack of a fuel cell system, the device comprising a heat exchanger which cools the cooling medium, a cooling passage through which the cooling medium is circulated between the fuel cell stack and the heat exchanger, a pump which pressurize the cooling medium in the cooling passage for circulation, a bypass passage which bypasses the fuel cell stack to directly circulate a part of the cooling medium discharged from the pump to the heat exchanger, an electrical conductivity reducing mechanism which reduces an electrical conductivity of the cooling medium passing through the bypass passage, a valve which regulates a bypass amount of the cooling medium passing through the bypass passage, the method comprising
- detecting an electrical conductivity of the cooling medium;
- determining if the electrical conductivity is larger than a predetermined conductivity;
- controlling the valve to increase the bypass amount when the electrical conductivity is larger than the predetermined conductivity;
- determining if a predetermined condition related to an operation of the fuel cell stack holds;
- and
- controlling the valve to prevent the bypass amount from becoming zero when the electrical conductivity is not larger than the predetermined conductivity and the predetermined operation condition holds.
Dependencies are inferred from the claim text.